Lewis k



L K. DAvls y Re' 15'935 GRIP PULLEY Original Filed June 12, 1922, A

r l, 7//64 b rae Reissued Oct. 28, 1924.

y UNITED STATES Re. 15,935l PATENT OFFICE.

LEWIS K. DAVIS, OF "WASHINGTON, DISTRICT 0F COLUMBIA.

GRIP PULLEY.

Original No. 1,481,376, dated October 10, 1922, Serial No. 567,847, led J'une 12, 1922. Application for reissue led Junev 18, 1923. Serial No. 646,250.

To all whom it may concern.'

Be it known that I, Lewis K. DAVIS, a citizen of the United States, residing in WashingtomDistrict of Columbia, have invented certain new and useful Improvements in Grip Pulleys, of which the following is aspecification.

This invention relates to sectional belt pulleys of the kind in which provision is made for firmly gripping the belt with which the -pulley is associated when there is a tendency Vfor the latter to slip on the former or where the pulley runs ahead of the belt, and the object of the invention is to provide means whereby when Vthe belt starts to slip it `will be automaticallygripped and carried forward without a preciable lost motion. f

Briefly stated, t e invention .consists 1n providing means whereby when the belt starts to slip it will cause one of the pulley sections `to automatically -move toward the other, or the grippingsections or members to 'be simultaneously moved toward each other in such manner as to cause the gripping membersto quickly grasp the belt Vso that the latter is driven forward without delore specifically, the preferred form of the invention consists in providing three fplille sections, two of which have gripping A io mem s engaging the belt and revolving 'witht'he axle, and a third or intermediate section Awhich is loose on the axle but is in ifric'tional engagement with the belt and moves 'coincidentally therewith. The a1'- Aran ment is such that when the belt-'starts to s ip, ithe movement of -the third =or intermediate section is retarded andcertain ldevices connecting the sections are 'brought into action which `immediately cause lthe fbelt to be firmly Agrasped rby the gripping 'membersanll moved forward Vin the normal gtie f'libly fthe its inbst 'approved folii, bwl) gripping sections to With'fa centrally arranged arb and adjustable 'end-wise off-the Aante and 'Au third fotil'rli 'bn the axle or abpgt the aits'th'ereof, bililt 'lliavrg i@ ,'p Y" in engagement wit -t 1e ylt so 5tl1titnim`ally nieves co-'i'ncidenta'lly with ithe gripping "'seetions. The 'hubs or bosses olf-the three sections have threaded connectiene 'with leach other `'so constructed 'that when the 1belt starts to slip `the gripping nous,

members'are made to grasp the belt in the manner 'before explained.

In the accompanying drawings Figure l is a view in vertical section of parts of a grip pulley embodying my inventlon.

Figure 2,is a diagram illustrating one of the uses of theinvention.

Figure 3 'is aperspective view of a portion of a belt which may be employed.

Figure '4 is a view of another form of belt which may be used.

VFigure 5 is a sectional view similar to Figure l showinga modification.

Figure 6 is a view on an enlar ed scale and in section on the line 6-6 of igure 5.

Figure 7 is a detail perspective view showing the screw threaded connections between thepulley sections in the form of pulley shown in 'Figure 1..

Figure 8 is a detail ,view illustrating the cams yforming Vpart of the modified construction shownjin Figure 5.

The pulley` may be employed in various ways and for different purposes. For convenience I have herein shown it as applied to a belt or endless track such as 1s commonly usedjin tractors andsimilar vehicles.

The manner in which the pulley or pulleys A maybe associated with an endless belt B is indicated inFigure 2. The belt as shown in Figures 1, @and 3 is cformed with a centrall vrarrangedrib orflange b which is preferalo' y,though not necessarily, tapered. A1nstead of employing a continuous rib -I may 'use a broken rib or series of teethy b as indicated in Figure 4. The belt is made of The )pulley shown is made in three sec- Y pand Z. The sections X Vand Z are keyed to the axle C, while Vthe intermedia'te section Y lis loose on the axle.

Preferably the axila o :is mounted u) se.

at o, o to receive internal ribs on vt :e hubs or bosses of the sections Xa'nd Z.

The fse'ction Y isplaced the sections YX and -Z and-lhasfabushing 'y fitted to the `axle C so Vas -to turn Vfreely thereon. The sections X and Z are formed at, their outer ends or peripheral `Itions with gripping Ymem-bers w and zya apted to grasp the rib b of the belt and with 'flanges in', z

which make contact with the inner side of the belt B. The periphery y of the intermediate section Y makes contact with the inner portion of the rib b so that when the belt is moved, the section Y is revolved about the axis of the axle C.

The sections X and Z have inwardly ex tending annular flanges l which are screw threaded as shown and engage corresponding threads on the hub e of the section Y. Right and left hand threads are employed and the arrangement is such that when the section Y moves relatively to the sections X and Z or when the sections X and Z run ahead of the belt, the gripping sections will be moved towards each other and the rib of the belt Will be grasped by the gripping members and thereafter the belt will move forward with the pulley sections in the normal way. This operation is practically instantaneous and there is no appreciable lost motion in the operation of the mechanism.

If in the operation of the pulley the belt l starts to slip on the flanges m', a, the intermediate section Y will be retarded in its movement and owing to this relative movement, the screw threaded devices will operate to cause the gripping sections to grasp the belt instantl and cause it to move forward in the normalway with the pulley.

Instead of both sections X and Z being made movable endwise of the axle one only of the sections need be thus moved relatively to the other. In such case only one of the sections need revolve with the! axle at all times. The axle C 'is properly shouldered as indicated to receive the various sections of the pulley and when assembled in the manner shown in Figure 1 they may be held in place by a nut M and washer N or by other suitable devices.

A somewhat similar result may be ob tained by the construction illustrated in Figures 5 and 6. Where the parts are similar to those shown in Figure 1 they are similarly lettered. In this case, cam rings F are bolted to the section Y which co-opcrate with similar cam rings G bolted to the sections X and Z. When the sections X and Z slip under the belt and the section vY is thus retarded, the relative movement will cause the cam rings G to ride on the cams F and the sections X and Z will be drawn toward each other in such manner as to cause the rib b on the belt to be grasped by the. gripping members 'in the manner beyfore described.

I claim as my invention 1. A gzip pulley adapted to be associated with a ltand comprising a plurality of sections at least one of which is mounted to revolve at all times with a centrally arranged axle and another section mounted to turn about a fixed axis independently of the axle While engaging the belt, and means connecting the sections for causing them to grip the belt when the latter slips on the axle driven section.

2. A grip pulley adapted to be associated with abelt having a lrib or flange on its inner side and comprising two sections engaging the inner side of the belt on opposite sides of the rib and at least one, of which is ada ted to revolve at all times with a centra ly arranged axle and a third section mounted to turn independently of the axle while engaging the rib of the belt and means connecting the sections for causing them to grip the belt when the latter slips on the axle driven section.

3. A grip pulley adapted to be associated with a belt and comprising two sections mounted to revolve about the axis of a centrally arranged axle and at least one of which is mounted to revolve at all times with the axle and another section engaging the belt arranged between the others, mounted to turn independently of the axle about a fixed axis While engaging the belt, and means connecting the sections for causing them to grip the belt when the latter starts to slip upon the axle driven section.

4. A grip pulley adapted to be associated with a belt and comprising a plurality of sections, at least one of which is mounted to revolve at all times with a centrally arranged axle, a third section interposed between the others, engaging the belt and which is adapted to turn about the axis of the axle independently of the other sections, and a threaded connection between the several sections for causing the belt to be gripped by the sections when the belt starts to slip on the axle driven section.

5. A grip pulley adapted to be associated with a belt and comprising a plurality of sections, at least one of which is mounted to revolve at all times with a centrally arranged axle and another section mounted to turnl independently of the axle while engaging the belt, and a right and left hand threaded connection between the sections operated by the belt for automatically causing them to grip the belt when the latter starts to slip on the axle driven section.

6. A grip pulley associated with a belt and comprising two sections mounted to revolve about the axis of a centrally arranged axle and one of which is movable endwise of the axle toward the other to cause the gripping parts to grasp the belt, another pulley section interposed between the others engaging the belt and mounted to'turn on the axle about a fixed axis, and means connecting the several sections for movig the gripping members into firm engagement with the 7. A grip pulley associated with a belt and comprising two sections mounted to revolve about the axis of a centrally arranged axle and one of which is movable endwise of the lol axle toward the other to cause the gripping members to grasp the belt, another pulley section engaglng the belt interposed between the others and mounted to turn on the axle, and a threaded connection between the sections for moving the gripping members into firm engagement with the belt.

8. A gri pulley adapted to be associated with a be t and comprising two sections mounted to revolve about the axis/of a centrally arran d axle and one of which is movable endgvsise of the axle to cause the gri ping members to grasp the belt, another ulley section interposed between the others and having a threaded hub engaging Va threaded part of at least one of the other sections.

9. A gri pulley adapted to be associated with a be t having a rib or flange on its inner side comprising two sections engaging the inner side of the belt and engaging opposite sides of the rib and at least one of which is adapted to revolve at all times with a centrally arranged axle and a third section mounted to turn independently of the axle about a fixed axis while en aging the belt rib, and means connecting tie sections for causing them to grip the belt when the latter slips upon the axle driven section.

10. A grip pulley adapted to be associated with a belt having a rib or flange on its slipping of the belt to cause the second section to move toward -the first to grip the rib of the lbelt between the two sections.

11. A grip pulley adapted to be associated lwith a belt having a rib or fiange on its inner side comprising a section which is mounted to turn at all times with the axle, a second section opposing the first, a third section engaging the rib on its inner side, and means operated solely by the slipping of the belt to cause a relative movement between the two sections to grip the rib of the belt.

12. A grip pulley adapt-ed to be associated with a belt having a rib or flange` on its inner side comprising a section which is mounted to turn at all times with the axle, a second section opposing the first, a third section engaging the rib on its inner side, and means operated by the slipping of the belt to move the second section in a right line towards the other to grip the rib of the belt..

In testimony whereof, I have hereunto subscribed my name.

LEWIS K. DAVIS. 

